Conventionally, cooling devices employing air cooling are included in electronic devices, for example. In the air cooling, a heat sink is attached to a heating element, such as a central processing unit (CPU), and air generated by a fan is blown onto the heat sink to cool the heating element. There are also cooling devices that use water cooling. In the water cooling, a radiator cools a working fluid warmed by heat received from a heating element, and the cooled working fluid is returned to a place where the cooled working fluid is to receive heat again.
Air cooling or simple water cooling may sometimes be insufficient to cool heating elements that are included in electronic devices with enhanced functionality and high output power, for example, and that generate a great amount of heat. Thus, cooling devices utilizing latent heat of vaporization, such as a cooling device described in Unexamined Japanese Patent Publication No. 2012-26721, have been proposed. These cooling devices utilize latent heat of vaporization required for a working fluid to change from a liquid phase to a gas phase, to cool a heating element with high efficiency.